Tumbling of polymers in semidilute solution under shear flow

TL;DR

This study uses large-scale simulations to analyze polymer tumbling in semidilute solutions under shear flow, revealing concentration-dependent dynamics and universal behavior due to hydrodynamic screening.

Contribution

It provides new insights into the tumbling dynamics and universal behavior of polymers in semidilute solutions under shear flow through mesoscale hydrodynamic simulations.

Findings

Tumbling time equals the polymer's non-equilibrium relaxation time.

Tumbling frequency shows weak concentration dependence in the crossover regime.

Universal behavior emerges in semidilute solutions due to hydrodynamic screening.

Abstract

The tumbling dynamics of individual polymers in semidilute solution is studied by large-scale non-equilibrium mesoscale hydrodynamic simulations. We find that the tumbling time is equal to the non-equilibrium relaxation time of the polymer end-to-end distance along the flow direction and strongly depends on concentration. In addition, the normalized tumbling frequency as well as the widths of the alignment distribution functions for a given concentration-dependent Weissenberg number exhibit a weak concentration dependence in the cross-over regime from a dilute to a semidilute solution. For semidilute solutions a universal behavior is obtained. This is a consequence of screening of hydrodynamic interactions at polymer concentrations exceeding the overlap concentration.